This invention relates to an apparatus and method for separating and moving a group or xe2x80x9clogxe2x80x9d of interfolded sheets from the discharge of an interfolding apparatus, such as a pair of folding rolls.
In forming packaged interfolded sheets, such as papertowels, a pair of webs are cut into individual sheets, and the sheets from each web are supplied to one of a pair of cooperating folding rolls. The folding rolls function to interfold the sheets in a conventional manner, and the interfolded sheets are typically discharged in a vertical stack. When a desired sheet count is attained, separating fingers are inserted into the stack for separating a lower portion of the stack from the remainder of the stack, for subsequent processing, such as wrapping the stack and cutting the stack in individual sections corresponding to a pack of interfolded sheets.
An example of a separating system is disclosed in U.S. Pat. No. 4,770,402. In this system, a finger is inserted into the stack discharged from the folding rolls when a predetermined sheet count is attained. The finger supports the sheets located above the finger and below the folding rolls. The sheets below the finger, which comprise the sheets to be separated and discharged for subsequent processing, are supported by a support member and another finger, which move downwardly after the first finger has been inserted into the stack for supporting the sheets thereabove. Downward movement of the support member and the second finger separate the sheets below the first finger from the sheets above the first finger. While this type of discharge system is functional to separate a predetermined number of interfolded sheets from a stack, it involves disadvantages associated with support of the stack and downward movement of the section of the sheets which are separated from the stack.
It is an object of the present invention to provide an improved arrangement for separating a predetermined number of interfolded sheets from a series of interfolded sheets discharged from a folding arrangement. It is another object of the invention to provide such a system which takes advantage of a separation in the interfolded sheets to separate an endmost group of sheets from the remainder of the sheets without relative axial movement of the endmost sheets from the remainder of the sheets. It is a further object of the invention to provide such a system which accomplishes separation of the endmost group of sheets by moving the endmost group of sheets in a transverse direction relative to the remainder of the sheets. A still further object of the invention is to provide such a system which accomplishes separation of the endmost group of sheets without vertical movement of the sheets. Yet another further object of the invention to provide such a system which accomplishes separation of the endmost group of sheets without having to provide a vertical support for the remainder of the sheets. A still further object of the invention is to provide such a system which is relatively simple in its components and operation, and which provides significant advantages in separation and discharge of a group of sheets from a folding arrangement and for subsequent processing of the group of sheets.
The invention contemplates a method of separating a group of interfolded sheets from a series of interfolded sheets discharged from a sheet folding arrangement, such as a pair of folding rolls. The sheets are discharged from the folding arrangement in a first direction. The invention involves forming intermittent separations in the interfolded sheets, which function to separate the interfolded sheets into groups of interfolded sheets, including an endmost group of sheets. The invention further involves engaging the endmost group of sheets with a clamping mechanism, and moving the clamping mechanism laterally in a direction transverse to the first direction so as to exert a pulling force on the endmost group of sheets. The separation between the endmost group of sheets and the next adjacent group of sheets functions to enable the endmost group of sheets to separate from, and move laterally relative to, the next group of sheets, so as to separate the endmost group of sheets for subsequent processing.
The sheets are initially discharged from the folding arrangement in a substantially vertical direction, and the invention involves altering the direction of movement of the sheets from the vertical direction prior to engagement of the endmost group of sheets with the clamping mechanism. In a preferred form, the direction of movement of sheets is changed from vertical to horizontal, such that the endmost group of sheets is supplied by substantially horizontal movement to the clamping mechanism. A guide arrangement is located at the discharge of the folding arrangement for receiving the sheets from the folding arrangement and initially forming a vertical stack of sheets, and for thereafter guiding movement of the sheets from vertical to horizontal. The guide arrangement discharges the sheets to a support surface of a discharge table, which may be provided with a series of belts for moving the sheets horizontally on the support surface. A series of pivotable fingers engage the end of the stack of interfolded sheets as the sheets are supported on the support surface of the discharge table. Engagement of the fingers with the end of the stack prevents the sheets from falling over onto the support surface of the discharge table as the sheets are moved on the support surface.
The clamping mechanism includes a pair of clamping members which are operable to engage the endmost group of sheets. A first clamping member is movable from an inoperative position above the sheets, to an operative position in which the first clamping member is inserted into the endmost group of sheets at a location outwardly of the separation between the endmost group of sheets and the next adjacent group of sheets. A second clamping member engages the outermost sheet in the endmost group of sheets, and is movable toward the first clamping member for exerting a clamping force on the sheets between the first and second clamping members. The clamping members are preferably located so as to engage the sheets toward and of the endmost group of sheets. Operation of the clamping members may be initiated by sensing movement of the fingers which support the sheets in the endmost group of sheets.
Once the sheets are clamped between the first and clamping members, the clamping members are moved laterally in a direction transverse to the direction of movement of the sheets on the support surface. The sheets are preferably pulled by the clamping mechanism in a direction along the longitudinal axis of the group of sheets, by virtue of the tensile strength of the group of sheets. The separation between the endmost group of sheets and the next adjacent group of sheets enables the endmost group of sheets to separate from the next adjacent group of sheets when the endmost group of sheets is moved laterally by the clamping mechanism. The clamping mechanism is moved laterally a distance sufficient to enable the end of the endmost group of sheets to clear the next adjacent group of sheets, such that the endmost group of sheets is fully discharged from the stack of sheets. The endmost group of sheets is preferably moved onto a transfer table into a space between guides which extend upwardly through slots formed in the transfer table. After the endmost group of sheets is fully discharged from the discharge table, the first and second clamping members are released from engagement with the sheets and moved laterally so as to clear the end of the group of sheets. The guides are then moved within the slots so as to move the sheets laterally on the transfer table, for subsequent processing.
The invention further contemplates an apparatus for separating a group of interfolded sheets from a plurality of groups of interfolded sheets supplied by a folding arrangement, substantially in accordance with the foregoing summary.